Cell type-specific mechanisms of voltage-dependent spike frequency modulation in the insect olfactory system.

中枢神经系统由多个神经元回路组成，确保有效地执行许多不同的任务。这些网络的任务特异性功能和计算特征是由内在的细胞特性和网络组成神经元之间的突触连接所控制的。通常，这些回路中的神经元具有高度特化的生理和形态表型。节肢动物和脊椎动物进化出的初级嗅觉系统是明确的、特定任务的、高性能神经回路的突出例子。这些电路在不同的门之间有着相似的结构和处理原理。基于广泛的研究，人们对嗅觉信息是如何被处理的，以及昆虫触角叶（相当于脊椎动物嗅球的功能）中的神经元是如何对气味做出反应的，已经有了一个大致的了解。然而，虽然神经元的气味反应显然是由它们的突触输入和内在电生理特性决定的，但令人惊讶的是，我们对它们的细胞类型特异性的内在特性以及它们如何在不同的神经元中形成气味反应知之甚少。然而，由于组成神经元的特性最终决定了网络的功能，因此定义细胞类型特异性电生理表型是现实（计算）模型的基础，也是真正理解嗅觉信息处理机制的先决条件。因此，该项目旨在定义细胞类型特异性功能表型，并确定介导它们的主要离子电流。重点是在昆虫嗅觉系统中起关键作用的2种神经元类型，抑制性gaba能多肾小球局部中间神经元和兴奋性单肾小球胆碱能投射神经元。在这种情况下，我们还讨论了昆虫物种之间观察到的保守电路组织是否与相似的固有电生理特性和离子机制有关。为此，对两种进化距离较远的昆虫——半代谢蟑螂P. americana和全代谢果蝇D. melanogaster进行了比较研究。

Central nervous systems consist of multiple neuronal circuits that ensure the efficient execution of many different tasks. These networks' task-specific functional and computational features are governed by the intrinsic cellular properties and the synaptic connections between the networks' component neurons. Typically, the neurons of these circuits have highly specialized physiological and morphological phenotypes. Prominent examples of defined, task-specific, high-performance neuronal circuits are the primary olfactory systems that have evolved in arthropods and vertebrates. These circuits share similar architectures and processing principles across phyla.Based on extensive studies, there is a general understanding of how olfactory information is processed and how the neurons in the insect antennal lobe, the functional equivalent of the vertebrate olfactory bulb, respond to odors. Nevertheless, while it is evident that the neurons' odor responses are determined by their synaptic input and intrinsic electrophysiological properties, surprisingly little is known about their cell type-specific intrinsic properties and how they shape odor responses in the different neurons. However, since the properties of the component neurons ultimately determine the function of the network, defining the cell type-specific electrophysiological phenotypes is the basis for realistic (computational) models and the prerequisite for a truly mechanistic understanding of olfactory information processing.Accordingly, the project aims to define cell type-specific functional phenotypes and identify the main ionic currents that mediate them. The focus is on 2 neuron types that play a crucial role in the insect olfactory system, the inhibitory GABAergic multiglomerular local interneurons, and the excitatory cholinergic uniglomerular projection neurons. In this context, we also address whether the conserved circuit organization observed between insect species is associated with similar intrinsic electrophysiological properties and ionic mechanisms. For this purpose, the studies are performed comparatively on two evolutionarily distant insect species, the hemimetabolous cockroach P. americana and the holometabolous fruit fly D. melanogaster.